JPH0442795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric screen generating device for generating an electric screen for blocking the swimming of fish and shellfish in seawater when cultivating fish and shellfish.

[Conventional technology]

Generally, when cultivating fish and shellfish, a cage is set up in seawater, and the fish and shellfish are cultured within the cage.Usually, a net is stretched around the seawater to form a cage, and the net is used to extend the fish and shellfish to the outside of the cage. This prevents fish and shellfish from escaping and entering the inside of the cage, but at the early stage of aquaculture, farmed fish are still young fish with a body length of several centimeters, and this prevents the swimming of these young fish. In this case, it is necessary to use a very fine mesh net to be placed in the seawater.

However, in sea areas where tidal changes can be as large as several meters, the nets are easily damaged, and even if the damage is slight, young fish can easily escape, resulting in the inconvenience of requiring a great deal of effort and expense to maintain and maintain the nets. occurs,
In order to eliminate these inconveniences, conventionally, the sea areas where the fish cages are installed are selected in areas where the water depth is not too deep, the waves are calm, and there are few tidal changes, but even in areas that meet these conditions, typhoons The nets may be washed away due to water pollution, etc., or damaged due to contact with ships, which requires a great deal of effort and expense to maintain and maintain the nets, and the nets cannot reliably block the swimming of fish and shellfish. There is a problem.

In addition, when carrying out large-scale aquaculture such as on marine farms, the total length of the nets used is extremely long, and the labor and expense required to maintain and maintain the nets are correspondingly large. Using nets for isolation is not the best strategy for large-scale aquaculture.

Therefore, the present applicant has proposed an electric screen generator shown in FIG.

That is, as shown in FIG. 7, a plurality of vertical rod-shaped conductive electrodes 1a are arranged in seawater at approximately equal intervals, and each conductive electrode 1a is electrically connected to each other by a connecting body 2a, so that one electrode forming column 3a;
Similarly, a plurality of vertically extending bar-shaped conductive electrodes 1b are arranged in seawater at approximately equal intervals with the same pitch as in the case of the electrode row 3a, and each conductive electrode 1b is electrically connected to each other by a connecting body 2b. An electrode row 3b is formed, both electrode rows 3a and 3b are arranged parallel to each other,
A power source for generating an electric screen applies, for example, a DC voltage between both electrode rows 3a and 3b so that one electrode row 3a is at ground potential and the other electrode row 3b is at a predetermined potential. , 3b to generate an electric screen with a predetermined electric field strength.

Fish and shellfish that have entered such an electric screen are electrically stimulated, and when the electric field strength of the electric screen is low, they exhibit a startled state, and as the electric field strength increases, they experience slight numbness, paralysis, and even paralysis. If a person exhibits an electric shock reaction such as asphyxia and is unable to swim through the electric screen, and if both electrode rows 3a and 3b are arranged so as to surround a specific area with the electric screen, Fish and shellfish will be confined within the area, and swimming of fish and shellfish will be reliably blocked without using nets as in the past, and it will be affected by ocean conditions such as tide level, tide, water depth, and weather conditions such as typhoons. It is suitable for large-scale aquaculture such as marine farms.

[Problem that the invention seeks to solve]

However, in this case, the interval between each electrode 1a, 1a, ... or 1b, 1b, ... and both electrode rows 3a, 3
If b is set appropriately, the rate of blocking fish and shellfish by the electric screen, that is, the rate at which swimming passage of fish and shellfish is blocked, is low compared to the power supplied by the power supply, increasing power consumption and effectively blocking swimming of fish and shellfish. The problem is that it cannot be done.

Therefore, this invention aims to reduce power consumption,
The technical challenge is to efficiently block the swimming of fish and shellfish.

[Means for solving problems]

The present invention has been made with the above points in mind, and includes a plurality of electrode rows in which a plurality of conductive electrodes are arranged in seawater at approximately equal intervals and arranged in parallel to each other; comprising a connection body that electrically connects each of the conductive electrodes of each electrode row to each other, and a power source for generating an electric screen that applies a voltage between each of the electrode rows so that the potentials of each of the electrode rows are different; The electrical screen generating device is characterized in that the ratio of the spacing between the electrode rows to the spacing between the conductive electrodes is greater than about 0.5.

[Effect]

Therefore, in the present invention, each electrode row is arranged such that the ratio of the spacing between each electrode row to the spacing between each conductive electrode in each electrode row is greater than about 0.5, and The electric field strength and resistance of the electric screen formed in the screen are both close to the theoretical values, and at the same time, a high swimming blocking rate for fish and shellfish can be obtained with low power consumption.

〔Example〕

Next, the present invention will be explained in detail with reference to FIGS. 1 to 6 showing one embodiment thereof.

In FIG. 1, the same symbols as in FIG. 7 indicate the same or corresponding items, and 4 indicates both electrode rows 3.
This is a power source for generating an electric screen that applies a DC voltage between a and 3b.The difference from FIG.
Both electrode rows 3a and 3b are arranged so that the relationship between b and interval Y is X/Y>0.5.

Then, when changing the ratio of the above-described intervals X and Y, that is, the value of X/Y, both electrode rows 3a,
Theoretical value of the electric field strength of the electric screen between 3b Et
As a result of investigating how the ratio of the actual measured value Er to the resistance value Er/Et and the ratio of the actual measured value Rr to the theoretical value Rt of the resistance value Rr/Rt change,
As shown in Figures 2 and 3, respectively,
When X/Y is greater than approximately 0.5, Er/Et, Rr/
Both Rt values are close to "1", indicating that at this time, the measured values of the electric field strength and resistance value of the electric screen are both closest to the theoretical values.

In addition, the distance X between both electrode rows 3a and 3b is 50 cm,
As a result of investigating the relationship between the voltage applied by the power source 4 and the electric field strength and current of the electric screen in the case of 100 cm, the results are shown in Figures 4 and 5, respectively, and the solid lines in Figures 4 and 5 are as follows. X=
In the case of 50cm, the dashed line indicates the case of X = 100cm,
If the distance X becomes 1/2, both the electric field strength and current will double for the same applied voltage.

Furthermore, as a result of investigating the relationship between power consumption and the blocking rate of fish and shellfish by the electric screen, that is, the rate at which swimming passage is blocked, when X/Y is 0.1, 0.2, and 0.5, respectively, the results are as shown in Figure 6. In Fig. 6, the dashed line shows the case when X/Y=0.1, the broken line shows the case when X/Y=0.2, and the solid line shows the case when X/Y=0.5, so when X/Y is 0.1 or 0.2 If X/Y is smaller than 0.5, no matter how much the power supplied by power source 4 is increased, swimming of fish and shellfish cannot be prevented; however, if X/Y is 0.5, the power supplied by power source 4 This means that swimming of fish and shellfish can be almost completely prevented with just 0.5KVA of electricity.

Therefore, from the data shown in FIGS. 2 to 6, by making X/Y larger than about 0.5, swimming of fish and shellfish can be almost completely prevented with small power consumption.

Note that the conductive electrodes 1a and 1b are not limited to the rod-shaped ones described above.

Furthermore, it goes without saying that the power supply 4 may apply an alternating current voltage or a pulse voltage between the electrode rows 3a and 3b.

Furthermore, even if three or more electrode rows are provided, the present invention can be implemented in the same manner.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, the ratio of the spacing between each electrode row to the spacing between each conductive electrode is greater than about 0.5, so that fish and shellfish can be efficiently grown with less power consumption. Swimming can be almost completely prevented, and the effect is extremely large.

[Brief explanation of drawings]

1 to 6 show one embodiment of the electric screen generator of the present invention, FIG. 1 is a schematic diagram, and FIGS. 2 and 3 are the ratios of the spacing between electrode rows to the spacing between conductive electrodes, respectively. Figures 4 and 5 are relationship diagrams between applied voltage, electric field strength, and current, respectively, and Figure 6 is power consumption and interruption rate. FIG. 7 is a perspective view of an electric screen generator to be compared with the present invention. 1a, 1b... conductive electrode, 2a, 2b... connection body, 3a, 3b... electrode row, 4... power source.

Claims (1)

[Claims] 1. A plurality of electrode rows in which a plurality of conductive electrodes are arranged in seawater at approximately equal intervals and arranged in parallel to each other, and each of the conductive electrodes in each of the electrode rows is electrically connected to each other. a connecting body;
and a power source for generating an electric screen that applies a voltage between the electrode rows so that the potentials of the electrode rows are different, and the ratio of the spacing between the electrode rows to the spacing between the conductive electrodes is about 0.5. An electric screen generating device characterized in that the screen is larger than the above.